A gas barrier film may be preferably used as a packing container for filling and packing articles such as drinks and foods, cosmetics, and detergents. In recent years, there has been a proposal for the use of a laminate film having gas barrier properties (hereinafter, the film will sometimes be referred to as a “laminate film”) that is obtained by using a plastic film or the like as a substrate and layering a thin film, which is formed of a substance such as silicon oxide, silicon nitride, silicon oxynitride, or aluminum oxide, on one surface of the substrate.
Among known methods of forming a thin film layer of such an inorganic substance on the surface of the plastic substrate, physical vapor deposition (PVD) methods such as those for vacuum deposition, sputtering, and ion plating, and chemical vapor deposition (CVD) methods such as those for low pressure chemical vapor deposition and plasma-enhanced chemical vapor deposition are known. For example, PTL 1 describes a laminate film having a thin film layer which contains silicon, oxygen, and carbon and in which an average atomic ratio of carbon is 10.8 at % or less.